Power operated brake



Oct. 22, 1940.

J. R. ALMOND ET AL POWER OPERATED BRAKE Filed June 25, 1959 4Sheets-Sheet 1 F z. Z0 10 5 a v 6 2? Vacuum JasPa/zzsz: 3 a 4 5 15 5/ Il T 7 V 9 "m 9 5 A INVENTORS zaraafh/ UPPd/W/ (/a/w 541mm BY ATTORNEY.

Oct. 22, 1940. J R ALMOND AL 2,219,062

POWER OPERATED BRAKE Filed June 23, 1939 4 Sheets-Sheet 2 CO/VI'EOZDEAL/6 P615466 Pas/770A fl/E SUSPENDED 620 866 MUPP arm INVENTORS Jay/vE 4070MB ATTORNEY.

Oct. 22, 1940. J. R, ALMOND r AL 2,219,062

POWER OPERATED BRAKE Filed June 23, 1959 4 Shets-Sheet S 92 5644 5HPPUEZJ ATTORNEY.

Oct. 22, 1940.

J. R. ALMOND El AL POWER OPERATED BRAKE 650665 h/UPP and 1N VENTORS Zia,M

ATTORNEY.

Patented Oct. 22, 1940 UNITED STATES 2,219,662 rowan OPERATEDBRAKE JohnR. Almond; Cleveland, and George W. Upp,

Lakewood, Ohio, assignors to The Midland Steel Products Company,Cleveland, Ohio, a corporation of Ohio Application June 23, 1939, SerialNo. 280,853

18 Claims.

vide for improved operation of the brake with a special type of valvehaving a diaphragm which not only serves the usual function of apressure responsive partition, but is provided with a floatmg metallicseat by which asingle floating valve is operated to control pressures inthree different chambers without using the material of the diaphragin asa valve seat. This diaphragm material used in such devices, beingsubjected to II moisture and gasoline vapors and being flexed and seatedadjacent its central opening, proves very detrimental to longevity andserviceability of the valve seat, so that elimination of the diaphragmmaterial from wear and tear of its service as a valve seat, enhances thelife of the valve very materially. Thus, a valve is provided which isfreer from leakage than those using the diaphragm material as a valveseat and will maintain the desired' degree of vacuum for longer periodsof time.

In the field of vacuum brakes for trucks and trailers of so manyexisting models, varieties and combinations, there is occasion fortheuse of varied systems of hookups, with demand for flexibility ofequipment and ease of conversion to meet the various conditions andrequirements in the field. Therefore, another aim of the invention is'toprovide valves with inexpensive and durable parts which can be usedinterchange- 5 ably in different valves to reduce their cost ofproduction, maintenance and their cost to users of this equipment. v vAnother important object of the invention is to provide means in a truckand trailer installa- 40 tion' for reducing the time required to obtainmaximum application of the brakes on the trailer while maintainingtrailer reservoir pressure.

Another object of the invention is to provide relay valves which can bepartly made up from 45 parts of the foot control valve, and can bereadily converted for use in either air or vacuum sus-' pended trailerbrakes.

Other objects and advantages of the invention will become apparentduring the course of the 50 following description.

In the accompanying drawings forming a part of the application andwherein like numerals are employed to designate like parts throughoutthe several views,

Fig. 1 is a layout showing the improved foot control valve installed inhydraulic brake system,

Fig. 2 is an enlarged side elevation of the foot control valve,

Fig. 3 is a longitudinal section 'of the same taken on the line 3-3 ofFig. 2,

Fig. 4 is a longitudinal section of the improved form of relay valve,

Fig.5 'is a layout showing the installation of the relayvalve in thetrailer brake system,

Fig. 6 is a longitudinalsection through a modi- 1o fied form of thisrelay valve,

Fig. 7 is a layout showing the latter installed in the brake system of atrailer,

Fig. 8 is a longitudinal section of another modifled form of relayvalve.

Referring now more particularly to the drawings and to Fig. 1, thenumeral l designates the usual. foot brake pedal of an automotivevehicle having a rod section 2 connected by a lost motion device 3 to arod section and valve carrier 4. 20 This latter rod section 4 isconnected to a brake cross shaft 5 by means of a lever 6. The means forpower operating this brake shaft is the usual vacuum power actuator I orcylinder having a I pressure operated piston therein,- the rod 8 of 25which is pivotally connected to a'lever 9 fastened to the brake shaft.This brake shaft may be connected with a mechanical brake operatingmechanism, or by means of a lever i0 may operate the piston rod H ofahydraulic master cylinder I2 30 which forces the hydrauic medium to theindividual brakes at the wheels through the piping l3 in the usualmanner.

The foot controlvalve is connected by a flexible pipe ll with a vacuumpipe l5 having a check valve therein and leading from the intake manifold it back to'a coupling I! which has a pipe I8 leading to. the rearend of the power cylinder and a pipe [9 leading to the rear end of thevehicle where it may be connected with a trailer in- 40 stallation.Another flexib ejgpipe 20 is also connected with the foot con i l valveand extends rearwardly to a coupling I which branches to a pipe 22connected with the forward end of the power chamber 1. From the coupling20 extends a pipe 23 to the rear end of the vehicle for connection withthe piping of a trailer connection as will be presently described.

The control valve casing V is composed of a pair of sections 24 and 25having complementary flanges connected together with bolts 26. Thesection 25 is provided with a fin like extension 21 which is fastenedbetween a pair of carrier links 28 forming an extension of the rodsection. A. The rod section 2 terminates in an angular end which ispivotally connected to the upper end as at 23 of a valve operating lever30 fulcrumed at 3| between the carrier links 25. The lower end of thislever 35 is pivotally connected as at 32 to the forward end of a valverod 33 which extends through a small rubber boot 34 and into the axialpocket 35 of the reduced end 35 of a valve member 31. This reducedportion 35 of the valve member is slidably mounted through an opening incasing section 25, which opening is packed with a packing g'land 35. Theforward wall of this casing section is provided with a port which isconnected by the flexible piping H to the intake manifold by means ofthe conduit I5.

These two casing sections 24 and 25 provide a cavity which is dividedinto a pair or chambers 45 and 4| by means of a flexible diaphragm 42,the periphery of which is securely clamped between the complementaryflanges of .the two housing sections as illustrated. The tubular sleevevalve body 31 extends through the center ofthis diaphragm and isprovided with a shoulder 43 adapted to engage an inwardly extendingtubular extension of the casing section 25 to limit the retraction ofthe valve in release position. The valve sleeve adjacent the shoulder43, is provided with slots 44 by which communication is had between thechambers 45 and 4| when the valve is in release position. A secondannular shoulder 45 is provided upon the sleeve adjacent an externalthreaded portion, whereby a pair of washers 45 arranged on oppositesides of the diaphragm are clamped thereto by threading a nut 41 uponthe sleeve valve as illustrated. In order to normally urge the valvetoward release position, a conical compression spring 48 is arrangedbetween the washer in chamber 4| and a partition 49 which separates thechamber 4| and a higher pressure chamber 50. The chamber 4| is providedwith a threaded port to which the conduit 20 is connected fortransmitting. pressure in this chamber to the brake cyl inder 1.

The partition 49 is provided with an opening 52 much larger than andconcentric with the end of the sleeve valve 31, the latter beingdisposed normally in close proximity thereto as illustrated in Fig. 3.This opening is surrounded by an annular valve seat 53 arranged inchamber 50 to form by reason of a conical compression spring '55 havingone end engaging the disk and its opposite end bearing against aremovable cover plate 51 provided with an apertured central depressionto receive and center one end of the spring. This cover plate isreceived in an annular groove in the casing section 24 and is releasablyretained therein along with the inner flanged end of a filter cover bymeans of a spring snap ring 50. In order to limit the opening movementof the air valve 54 a valve disk guard 5| is supported adjacent theairvalve by means of its having a plurality'of' legs 52 encircling thespring 55 and bearing against the cover plate 51.

With the parts of the valve in the position shown in Fig. 3, the brakesare in release position with a lower pressure medium such as a partialvacuum existing in chambers 45 and H and thus into the forward end ofthe brake cylinder 1, due to the fact that the air valve 54 is in closedposition as illustrated. To apply the brakes, the

pedal l is depressed causing valve sleeve 31 to abut against the elasticwasher 55 to cut oi! the lower pressure in chamber 4| and also to theforward end of the brake cylinder 1. Thus, there is 31 will force theair valve 54 against the tension of the springs 55 and 45 and oil of itsseat so as to admit a higher pressure medium or atmospheric pressureinto'the chamber 4| and thus into the forward end of the brake cylinder.A vacuum condition being maintained in the rear end of the brakecylinder through pipe i5, the piston rod of the brake cylinder will becaused to be moved to the right of the flgure thereby turning the brakeshaft 5 in a counter-clockwise direction to'operate the master cylinderi2 and force the fluid medium to the individual wheel cylinders to applythe brakes. Due to the rod 4 being connected with the brake shaft, thevalve casing is, during this operation, carried slightly forward toagain place the valve in lapped position in the event the pedal is notdepressed further. A further depression of the foot pedal will cause theair valve toagain open and when the foot pedal is released, the usualretracting spring applied to the pedal or the springs in the individualbrake mechanisms at the wheels will cause the pedal to return to normalposition thereby relaxing tension upon both springs 45 and which returnsthe valve parts to their normal position shown in Fig. 3 whereby apartial vacuum is reestablished through the sleeve valve 31 and chamber4| to set up a vacuum condition on opposite sides of the piston in thebrake cylinder 1, which is of course, re-established in the pipe 23leading back to the rear end of the. vehicle for connection with atrailer mechanism to be de scribed.

It will be noted that the casing section 24 is provided with acylindrical depression 54 opposite the air chamber 50 for the purpose ofinterchangeability of this section for other forms of valves such asshown in Figs. 4 and 6 and when it is employed as the end section 24 ofrelay valves. In this event the bottom of the depression 54 is brokenthrough to communicate with the air chamber 55. and the side walls ofthe depression are tapped for engagement with the lower threaded end 55of an air cylinder 55 which replaces the air cylinder 59 shown in Fig.3, in which event an imperiorate cover plate 51 is employed in place ofthe perforated cover plate 51 in Fig. 3. The air filter 55 is ofenlarged capacity with an imperforate cover 51 and an enlarged centraltube 58 extending through the chamber 65 to a point in close proximityto the cover 51 where it is provided with a radial extension 59 having athreaded aperture to receive a screw for fastening the cover 51 in placeon chamber 55. This air cylinder 55 is filled with filtering material 1|such as hair which is somewhat sup-.- ported midway of the chamber by adisk 12 supported upon a shoulder of the tube 55. The bottom of thechamber 55 is provided with a plurality of openings 13 for the entranceof atmospheric air and for drainage of any moisture drawn into thefilter. Thus, this air filter forms an interchangeable part for the twoforms of relay valve shown in Figs. 4 to 8. Likewise the end casingsection 24 with its associated parts forms a second interchangeablesection for all valves, and parts corresponding to those in Fig. 3 aredesignated with corresponding numerals with prime coefficients added. 5

In Figs. 4 and 5, brake port 5| is connected by a conduit 15 to the rearend of an air suspended trailer brake cylinder 16 which has its forwardend open to the atmosphere through a filter 11. This brake cylinder 16has the usual piston therein and piston rod 18connected to a lever 19securedto a brake shaft 80 for the operation of a brake rod 8| leadingto the brake mechanism of the trailer. In Figs. 6 and 7 the brake port5| is connected by a pipe 8| to the forward end of a vacuum suspendedtrailer brake cylinder 92, the rear end of which is connected by pipe 83with a trailer vacuum reservoir 84. The brake cylinder piston rod 85 isalso connected with a lever 86 secured to a brake shaft 81 which isconnected to the brakes of the trailer through rod 88. The relay valvefor the trailer in both instances is designated by the numeral 90 and iscomposed of interchangeable parts as will now be described.

Referring more particularly to the form of relay valve shown in Figs. 4and 5, designed for a hook up of vacuum suspended tractor system and airsuspended trailer system, an intermediate casing section 9| .is securedto the casing section 24' to secure the diaphragm 42' therebetween andto form a substantially constant pressure chamber 92 between thediaphragm and a partition 93 in the casing section 9|. At the bottom ofthis chamber an air cleaner 94 is screwed into is composed of anL-shaped gasket held clamped against the bearing 95 by a sleeve,press-fitted into the partition.

The end of the valve sleeve 91 opposite the end which engages the airvalve 54', is reduced and threaded with exterior threads, the latterreceiving a nut 98 to clamp a pair of washers upon opposite sides of aflexible diaphragm 99,

with its outer margin clamped between housing section 9| and an outerhousing section I00. This diaphragm defines a control chamber IOIbetween it and the partition 93, and a negative pressure chamber I02between'it and the outer wall of the section I00. The control chamberIUI is provided with a port I03 to which a pipe I04 is connected forconnecting the relay valve with the control line 23 of the tractor. Thecover section I of the relay valve is provided with a port I05 intowhich is secured a pipe I06 leading to one end of a trailer reservoirI01, the'opposite end of the reservoir being connected by pipe I08.having a normally open check valve I08 such as shown at '230 in thecopending Kuiper application Serial No. 78,870, filed May 9, 1936, withthe vacuum pipe I9 of the tractor system. A compression spiral springI09 is placed betweenthe endwall of casing I00 and the diaphragm. 99 topredominate. over spring 56' at the other'endof the housing so that thesleeve valve 91 is normally held against the air valve 54' to unseatitso that atmospheric pressure exists in chamber 4I and in the right handend of brake cylinder 16 to be balanced against air pressure in theopposite end coming through the breather 11. Since the end of the sleevevalve 91 is sealed against the gasket 55 of the air valve,sub-atmospheric pressure from the reservoir is prevented from enteringbrake chamber M. This is the normal brake release position of the valveparts forthis type of relay valve. In this normal position. of the relayvalve of Fig, 4, sub-atmospheric pressure exists in chamber I 0| fromthe control line I04, but when an application of the brakes is made onthe tractor, atmospheric pressure enters chamber IN to move thediaphragm 99 to the left thereby permitting the air valve 54' to closewhile the cooperating end of the sleeve valve 91 is opened to connectbrake chamber 4| with the trailer reservoir I01 through the hollowsleeve valve so that sub-atmospheric pressure is created in pipe 15 andthe right hand end of brake cylinder 16 to move the piston rod 18 to theright of Fig. 5, thereby applying the brakes to the trailersimultaneously with the application of the brakes to the tractor. Thislowering of pressure in brake chamber 4I permits the atmosphericpressure in chamber 92 to counterbalance that existing in chamber IM tomove the sleeve valve to a position where its end engages the elasticwasher 55' of the air valve to maintain the valve parts in lappedposition in the event the operator on the tractor maintains the positionof the pedal to retain the tractor control valve in lapped position sothat the relay valve takes a corresponding position. When the tractorfoot pedal is released to brake release position, sub-atmosphericpressure is recreated in control chamber IOI so that atmosphericpressure in chamber 92 predominates and moves the valve sleeve 91 to theright to unseat the air control valve 54' and re-establish the airsuspended condition in the trailer brake chamber 16. Since atmosphericpressure will then exist upon opposite sides of diaphragm 42 withsub-atmospheric pressure existing on opposite sides of diaphragm 99, thespring I09 will predominate to hold the air control 'valve open in brakerelease position.

The relay valve shown in Figs. 6 and .7 is very similar to that shown inFigs. 4 and 5, except that it is used for a vacuum suspended trailersystem. Therefore, parts corresponding in the two figures are designatedby the same numerals with the addition of "prime coeflicients in Figs. 6and 7. In Fig. 6, the relay valve is shown in brake applied position,but in release position the modified form of sleeve valve IIO has itsend' disengaged from the elastic washer of the air controlled valve 54'so that a sub-atmospheric pressure exists in chamber 4| and the lefthand end of brake cylinder 82. This condition is achieved by providingslots III in the sleeve.

valve IIO so that the interior of the valve sleeve is at all times incommunication with the chamber 92', which in this instance is providedwith a port II2 for connection with pipe II3'leading to the vacuumreservoir pipe 83. Instead of both ends of the valve sleeve being openas in the modification shown in Fig. 4, one end is closed by a press fitplug II4 which prevents the pressure existing in control chamber I02from entering the .valve sleeve. The control chamber is provided with aport H5 connecting with pipe II6 which is adapted to connect with thecontrol line 23 of the tractor installation so that whatever pressurecondition is set up in the 'brake chamber 4|. of the tractor footcontrol valve, is also set up in control chamber I02. The chamber IOI'which in Fig. 4 was connected with the control line, is closed with aplug I I1 so that the chamberIUI receives whatever pressure exists innegative pressure chamber 92' through the groove II8 provided in bearing95' for the reception of a valve friction'spring H9 laid lengthwise inthe groove with one end hooking over the end of the bearing and theother end hooking over the end of the retainer ring I20, and the bowedintermediate portion of the spring frictionally engaging the valvesleeve IIII.

In brake release position, the air valve 54' is closed upon its seat 53by the spring 58' and the seating end of the valve sleeve III! isdisengaged from the air valve so that reservoir pressure in chamber 92also exists in brake chamber 4| and in both ends of the cylinder 82.This negative pressure condition also exists in chambers MI and M2 sothat the diaphragms 42' and 99' are in balanced condition. Uponapplication of the tractor brakes, higher pressure is admitted throughthe control line into chamber I02 which moves the valve sleeve II8 intoengagement with the air valve 54* to lift it from its seat 56',whereupon atmospheric pressure enters the brake chamber 4| and into oneend of the brake chamber 82 to apply the trailer brakes. in brakeapplied position this relation of valve parts is maintained in lappedposition so as to hold the trailerbrakes as long as desired. Whenthetractor brake pedal is released, a negative pressure is again set up incontrol chamber I82 and with the higher pressure existing in chamber 4|,the valve sleeve H8 is moved back to release position to disengage theair valve 5i andpermit it to cut off the brake chamber II fromatmospheric pressure, thereby returning the valve parts to brake releaseposition.

In order to speed the time for obtaining maximum vacuum in an airsuspended brake cylinder of a trailer installation involving a vacuumreservoir, the modified relay valve shown in Fig. 8,

use of relay valve parts such as shown in Fig. 4

with th addition of two more diaphragms and a check valve controllingthe reservoir connection. Thus, the parts of Fig. 8 which correspond tothose in Fig. 4 are designated withreference numerals corresponding tothose in Fig. 4. In addition to the two casing sections 24' and 9| whichwith the pair of diaphragms-divide the casing into a control chamber'A,and atmospheric pressure chamber B, a brake cylinder chamber C and anair chamber D; a casing section I25 is provided to'clamp against thediaphragm 99. A third diaphragm I26 is clamped between a spacer memberI21 and the section I25. A fourth diaphragm I28 is clamped between thespacer member I21 and an end cover I29, the latter providing a reservoirchamber G, and the space between the two diaphragms I26 and I28 defininga control chamber F.. The space between the two diaphragms 99 and I26defines an intake manifold chamber E which has a port I30 for conmeetingthis chamber with theintake manifold pipe of the engine on the tractor.The casing section I25 is provided with a longitudinally extending portI3I which connects to a port I 3I' leading into chamber A, while theother end connects with a port which leads into chamber F. A

When the tractor brake pedal is heldcompression coil spring I32 ispositioned between the two diaphragms II and I 28 to normally urge themapart. The two diaphragms! and I2! are spaced from one another by meansof their being connected with an open ended sleeve I33 which has itsouter forked end I48 engaged with a floating check valve I34 to.normally hold it away from its seat I 35 formed on casing section I28.This check valve I38 is similar to valve 54' and a compress on conicalspring I35 ispositioned between the valve and the end of a nipple I31providing a connection to the reservoir of the trailer.

It will be notedthat a washer I38 backs up the chamber E through sleeveI33, and the normal.

operation of the internal combustion engine maintains the reservoir atmaximum vacuum. In an air suspended trailer system, the air controlvalve 54' is heldoii of its seat by valve sleeve 91 so that air passesinto brake chamber C from D. Atmospheric pressure of course,"exists inchamber B while chamber A is subjected to a vacuum condition whichcarries over through passage I3I into chamber F. Thus, diaphragm 40 isair balanced and 98 is vacuum balanced so that the spring I32 holds thevalve 54' open against its spring 56. Also the diaphragms I28 and I28are balanced in vacuum so that the spring I32 also holds the check valveI34 oil of its seat I35 against the tension of spring I35.

When the brakes on the tractor are applied, a higher pressure enterscontrol chambers A and F thereby moving diaphragms Stand I26 toward oneanother. Upon initial action of this relay valve,'the valve sleeve 91moves to permit closing of the air valve 54' and subsequent opening ofthe sleeve to chamber C so that both the reservoir and manifold willmomentarily withdraw air from the brake chamber C. 'After this momentaryoperation and pressures in chamber C and G are equalized, the sleeve I33moved farther to the right permitting th check valve I 34 to close uponthe seat I35 which cuts off the reservoir from the low pressure chamberE. so that the manifold pressure in E can continue to reduce pressure inbrake chamber C without exhausting or further reducing reservoirpressure at the same time. Thus, we get a speedier initial action of thetrailer brakes and reach a maximum vacuum quicker with this arrangement.As soon asthe brakes are released and the positive pressures in chambersA and F are reduced to negative pressures, the spring I32 moves the 'twosleeves 91 and I33 in opposite-directions to open the check valve I34,whereby maximum vacuum can be quickly re-established in the reservo rsince the sleeve 91 has been closed by abutment with the air valve 58'to move it oil. of its seat to restore atmospheric pressure to thechamber C.

To assure proper valve movements under all conditions of operationpand abalance of pressure between the control and brake chambers in brakerelease position difierent sized washers or diaphragm plates givingdifferent effective areas to the diaphragms, are employed in the relayvalves.

In Fig. 4 the diaphragm plates of diaphragm 99 are 2 inches in diameterwhile those of diaphragm 42' are 2 inches in diameter.

In Fig. 6, the plates of diaphragm 99' are 2 inches in diameter whilethose of diaphragm 42' are 2 inches in diameter.

In Fig. 8 the diaphragm plates of diaphragms 42" and I28 are 2 incheswhile those of diaphragms 99 and I26 are 2 inches in diameter.

Having thus described the construction and operation of the devices itwill be understood that various modifications of parts and theirrelation may be made without departing from the spirit of the inventionor the scope of the appended claims.

We claim: 1

1. A vacuum control valve comprising a casing having a pressure chamberwith valve seat, an air valve disk with a seating face floatably mountedand normally urged with its seating face towards said seat, a diaphragmdividing said casing into a. pair of separate chambers and having ahollow hub normally communicating said pair of separate chambers andadapted to be moved to seat upon the seating face of said valve to cutoff communication between said chambers and to move said valve ofi ofits seat to establish communication between said pressure chamber andone of said separate chambers.

2. A vacuum control valve comprising a casing having a partition with aport therein, a valve seat surrounding said port, an air valve disk witha seating face floatably mounted with its seating face urged toward saidseat to cut off the entrance of atmospheric pressure into said casing, adiaphragm dividing said casing into separate chambers and having ahollow hub adapted to be moved to and from seating engagement with theseating portion of said valve and to move said valve off of its seat,and said hub causing said separate chambers to communicate whendisengaged from the valve and to out 0155 communication between saidchambers when engaged with the valve.

3. A vacuum control valve comprising a casing having a partition thereinprovided with an opening and a valve seat surrounding the same, a valvedisk on one side of the partition and provided with a. plain elasticface normally urged toward said seat, a diaphragm in said casing on theopposite side of said partition, an open-ended metallic sleeve carriedby the diaphragm and arranged co-axially of said opening and seat'wheredisk from its seat.

4. A vacuum control valve comprising a casing having a partition thereinprovided with an opening and a valve seat surrounding the same,

a. valve disk on one side of the partition and provided with a plainelastic face normally urged toward said seat, a diaphragm in the casingon the opposite side of said partition, an open ended metallic sleevecarried by the diaphragm and arranged co-axially of said opening andseat whereby limited axial movement of the sleeve in one directionengages the elastic face of the valve and removes it from its seat, andmovement in the opposite direction allows engagement of the elastic facewith its seat and causes disengage ment of the sleeve from said valve. r

5. A vacuum control valve comprising a casing having a partition thereinprovided with an open-' ing and a valve seat surrounding the same, a

valve disk on one side of the partition and provided with a plainelastic face normally urged toward said seat, a diaphragm in the casingon the opposite side of said partition, an open ended metallic sleevecarried by the diaphragm and arranged coaxially of said opening and seatwhereby limited axial movement of the sleeve in one direction engagesthe elastic face of the valve and removes it from its seat, andmovementin the opposite direction allows engagement of the elastic facewith its seat and causes disengagement of the sleeve from said valve,and spring means normally biasing the diaphragm in one direction topre-arrange the sleeve relative to the I valve.

6. A vacuum control valve for vacuum brakes comprising a casing having apair of partitions therein, one of said partitions having an opening anda valve seat and the other having a packing therein, said partition withthe valve seat and opening defining an air chamber between it and theend wall of the casing, the other partition dividing the casing into apair of compartments, a diaphragm in each compartment dividing it into apair of chambers, and each chamber havinga port through the casing.

7. A relay valve for vacuum brakes comprising a casing having a pair ofpartitions therein, one

mounted in said bearing and its other end engageable with said springclosed valve.

8. A relay valve for vacuum brakes comprising a casing having a pair ofpartitions therein, one

having an opening and valve seat and the other a bearing, said partitionwith the valve seat de-' fining an air chamber between it and the endwall of the casing, a spring closed valve normally urged upon said seat,the other partition defining one wall of a control chamber, saidpartitions defining an intermediate chamber, a diaphragm in each of thecontrol and intermediate chambers, the diaphragm in the intermediatechamber dividing it into a brake chamber and a negative pressurechamber, and a valve sleeve secured to both diaphragms with one endslidably mounted in said bearing and its other end en-, gageable withsaid spring closed valve, said sleeve when disengaged from said springclosed valve connecting said brake chamber and negative pressurechamber. I

9. A relay valve for vacuum brakes comprising a casing having a pair oipartitions therein, one

having an opening andvalve seat therein and the other a bearing, saidpartition with the valve seat defining an air chamber between it-and theend wall of the casing, a spring closed valve normally urged upon saidseat, the other partition defining one wall of a control chamber, saidpartitions defining an intermediate chamber, a diaphragm in each of thecontrol and intermediate chambers, the diaphragm in the intermediatechamber dividing it into a brake chamber and a negative pressurechamber, the other diaphragm in the control chamber dividing itintonegative pressure and variable pressure chambers, a valve sleeve securedto both diaphragms and having both ends open. and one of said ends beingengageable with spring closed valve.

10. A relay valve for vacuum brakes comprising a casing having a pair ofpa titions therepartition defining one wall of a control chamber,

said partitions defining an intermediate chamber, a diaphragm in. eachof the control and intermediate chambers, the diaphragm in theintermediate chamber dividing it into a brake chamher and a negativepressure chamber, the other diaphragm in the control chamber dividing itinto negative pressure and variable pressure chambers, a valve sleevesecured to both diaphragms and having one end open and. engageable withsaid spring closed valve and its other end closed, and said sleevehaving an opening between its ends always in communication with theinter-,

mediate negative pressure chamber.

11. A vacuum brake system including in conibination, a power chamber, avacuum reservoir, a manifold and a control line, of a relay'valve havinga valve normally open to the atmosphere and valve means normally open toconnect the reservoir and manifold, and means within the relay valve forclosing the air valve and opening the manifold to the power chamberprior to closing the reservoir off from the manifold upon operation ofthe relay valve to apply the brakes.

12. A vacuum brake system including .in combination, a power chamber, avacuum reservoir, a manifold and a control line, of a relay valve casinghaving a pair of normally open valves at opposite ends thereof, andadapted to close upon opposed seats, a central low pressure chamber, apair of open ended sleeves movable in opposite directions and adapted tohold said valves unseated, and a plurality of diaphragmssupporting eachsleeve and providing five compartments, one being connected with thereservoir and with the central low pressure chamber through one of saidsleeves, the second and fourth compartments being connected with thecontrol line, and the fifth compartment being connected with theatmosphere, and the second sleeve being movable to connect the lowpressure chamber with the power chamber.

13. A vacuum brake system including in combination, a power chamber, avacuum reservoir,

a manifold and a control line, of a relay valve dividing a portion ofthe casing into a pair of chambers one of which is a control chamber,the sleeve connected with said pair of diaphragms communicating at oneend with said manifold pressure chamber and having its opposite valveengaging end provided with openings, the other pair of diaphragmsconnected to the other sleeve defining a space divided by a partitioninto a control chamber and a high pressure chamber, and the outermostdiaphragm of said last named pair separating the high pressure chamberfrom a brake chamber.

14. A vacuum brake system including in combination, a power chamber, avacuum reservoir, a manifold and a control line, of a relay valve casinghaving a reservoir chamber at one end and an atmospheric chamber at itsopposite end and said chambers having opposed valve seats, valvesnormally urgedtoward said seats, a pair of open ended sleeves movable inopposite directions and adapted to normally seat against said valves andpress them oil. of their respective seats, a pair of diaphragmssupporting each sleeve, the innermost pair of diaphragms providing amanifold pressure chamber with a spring disposed therein for normallyurging the two sleeves outwardly in opposite directions, the pair ofdiaphragms connected with one sleeve and dividing a portion of thecasing into-a pair of chambers one of which is a control chamber, thesleeve connected with said pair of diaphragms communicating at one endwith said manifold pressure chamber and having its opposite valveengaging end provided with openings, the other pair of diaphragmsconnected to the other sleeve defining a space divided by a partitioninto a control chamber and a high pressure chamber, and the outermostdiaphragm of said last named pair separating the high pressure chamberfrom a brake chamber and said last named sleeve having one endcommunicating with said manifold chamber and its other end imperforateto engage its complementary valve and cut oil. communication betweensaid brake chamber and manifold chamber when it engages its respectivevalve.

15. A vacuum brake system including in combination, a power chamber, avacuum reservoir, a manifold and a control line; of a relay valve havingan air valve normally open to the atmosphere and a check valve normallyopen to connect the reservoir and manifold, means with:--

in the relay valve for closing the air valve and opening the manifold tothe power chamber while the check valve remains open, and means forclosing the check valve, to cut oil the reservoir from the manifold uponoperation of the relay valve to appi the brake. I

16. A vacuum 'ake system including in combination, a power chamber, avacuum reservoir, a manifold and a control line, of a relay valve havingan air valve normally open tothe atmosphere and a check valve normallyopen to connect the reservoir and manifold, means within the relay valvefor closing the air valve and opening the manifold to the power chamber,while the check valve remains open, means for holding the check valveopen until the air valve closes, and said last named means operating toclose the check valve when the pressurein the brake chamber andreservoir are substantially equalized.

17. A control valve comprising a casing having an air chamber with avalve seat, a valve normally urged with its seating face toward saidseat, a diaphragm dividing said casing into a pair of chambers andhaving a hollow hub normally communicating said pair of chambers andadapted to be moved to seatupon said valve to cut off communicationbetween said pair of chambers and to move said valve off of its seat toestablish communication between said air chamber and one of said lastnamed pair of chambers.

18. A control valve comprising a casing having a partition with anopening and a concentric valve seat dividing the easing into an airchamber and a brake chambe a valve in said air chamber normally urgedwith its seating face toward said seat, a diaphragm separating the brakechamber from a third chamber and having a hollow hub normallycommunicating said last two named chambers and adapted to be moved toseat upon said valve to cut ofl communication between said last namedpair of chambers and to move said valve ofi of its seat to establishcommunication between said air and brake chambers.

JOHN R. ALMOND.

GEORGE W. UPP.

